// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// Copyright (c) 2007 Novell, Inc. (http://www.novell.com)
//
// Authors:
//	Chris Toshok (toshok@ximian.com)
//
using System.Collections.Specialized;
using MvvmFx.Windows;

namespace MvvmFx.Collections.Specialized
{
    /// <summary>
    /// CollectionChangedEventManager
    /// </summary>
    public class CollectionChangedEventManager : WeakEventManager
    {
        internal CollectionChangedEventManager()
        {
        }

        public static void AddListener(INotifyCollectionChanged source, IWeakEventListener listener)
        {
            CurrentManager.ProtectedAddListener(source, listener);
        }

        public static void RemoveListener(INotifyCollectionChanged source, IWeakEventListener listener)
        {
            CurrentManager.ProtectedAddListener(source, listener);
        }

        protected override void StartListening(object source)
        {
            var inotify = (INotifyCollectionChanged) source;
            inotify.CollectionChanged += OnCollectionChanged;
        }

        protected override void StopListening(object source)
        {
            var inotify = (INotifyCollectionChanged) source;
            inotify.CollectionChanged -= OnCollectionChanged;
        }

        private void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
        {
            DeliverEvent(sender, e);
        }

        private static readonly object CurrentManagerLock = new object();

        private static CollectionChangedEventManager CurrentManager
        {
            get
            {
                lock (CurrentManagerLock)
                {
                    var manager = (CollectionChangedEventManager) GetCurrentManager(typeof (CollectionChangedEventManager));
                    if (manager == null)
                    {
                        manager = new CollectionChangedEventManager();
                        SetCurrentManager(typeof (CollectionChangedEventManager), manager);
                    }
                    return manager;
                }
            }
        }
    }
}
